Preparation of uniform poly-caprolactone Microparticles by membrane emulsification/solvent diffusion process

• Polycaprolactone particles have been produced by two processes: membrane emulsification and solvent diffusion.
• Uniform O/W emulsion with controlled size has been produced injecting the polymeric solution through the membrane.
• The dilution of the emulsion in an aqueous phase allowed the solidification of the polymer within the droplet.
• Particle size and size distribution have been controlled in the emulsification step.
• Particle shape and morphology have been controlled in the post-emulsification step.

Over the last decade, the use of polycaprolactone has attracted much interest in drug delivery compared to biodegradable polyesters derived from lactic and glycolic acids. The methodologies commonly used for the preparation of polycaprolactone microparticles are associated with many problems regarding the control of particle size and size distribution and particles morphology. Membrane emulsification/solvent diffusion processes offer great potentials in manufacturing particles. In this work, polycaprolactone microparticles with mean diameter of 20 μm, spherical shape and smooth surface have been successfully produced using the emulsification/solvent diffusion method. The fluid-dynamic and chemical parameters have been optimized to produce uniform particles with a span value of 0.5. The effect of process parameters controlling the solvent diffusion on the shape and surface morphology has also been investigated. The use of microporous membranes allowed the simultaneous particle size and size distribution control during the emulsification step. Also, the solvent diffusion permitted easy control of the size and morphology of particles during the solidification of polymer within the droplets.